Search Results (5,067)

Marine by-products, including fishery discards, seafood-processing residues, aquaculture wastes, crustacean shells, and seaweed-derived side streams, are heterogeneous feedstocks rich in proteins, lipids, minerals, chitinous materials, polysaccharides, and bioactive compounds. This review examines insect-mediated bioconversion as a controlled biorefinery strategy for transforming these unstable marine residues into functional aquafeed ingredients and value-added bioproducts. We compare major marine feedstock classes and industrially relevant insects, with emphasis on substrate–insect matching, moisture control, salinity, lipid and ash load, texture, spoilage risk, and safety. Particular attention is given to how marine substrates can tailor insect meal, insect oil, chitinous fractions, hydrolysates, frass, and functional feed additives. The review further summarizes aquafeed applications of insect-derived products, including fishmeal and fish-oil replacement, protein and amino acid quality, lipid enrichment, gut health, immunity, and disease resistance in aquatic animals. Microbiome-assisted strategies, such as fermentation, enzymatic pretreatment, and gut or substrate microbial management, are discussed as tools to improve substrate stability, digestibility, and product quality. Finally, safety, regulation, scale-up, life cycle assessment, and techno-economic issues are considered. Overall, marine insect biorefineries should be optimized not only for biomass yield, but also for product quality, traceability, and application-specific safety. Full article

Against the backdrop of the “storing grain in land and technology” strategy and pressing food security challenges, understanding biased technological progress in grain production is crucial. This study constructs a three-factor Constant Elasticity of Substitution (CES) production function—incorporating agricultural machinery, chemical fertilizer, and labor—and employs a normalized supply-side system with Nonlinear Seemingly Unrelated Regression (NLSUR) to analyze biased technological progress across 26 Chinese grain-producing provinces from 2004 to 2023. Total factor productivity (TFP) is also decomposed to assess this progress’s contribution. The results indicate that first, technological progress generally evolves along a “machinery–fertilizer–labor” path. Recently, the primary driver shifted from machinery to fertilizers, aligning with fertilizer reduction and green development policies. Second, TFP growth exhibits phased characteristics, declining during the post-agricultural tax reform period (2005–2013) and rising amid supply-side structural reforms and the “storing grain in technology” strategy (2014–2023). Third, marketization, demand, and digitalization promote fertilizer-oriented progress; specialization drives machinery-oriented progress; and road infrastructure facilitates labor-oriented progress. These results offer empirical evidence for policy evaluation and guidance for optimizing factor allocation, advancing the green transition, and safeguarding food security. Full article

DC series arc faults (SAFs) are a significant safety hazard on the DC side of photovoltaic (PV) systems, with current signals characterized by strong randomness, obvious non-stationarity, and concealed fault features, posing challenges for rapid and accurate detection. With the development of application models such as agricultural PV integration, photovoltaic greenhouses, solar-powered irrigation, and livestock energy supply, the demand for the safe operation of photovoltaic systems in agricultural production scenarios is becoming increasingly prominent. To address the difficulty in fully characterizing the multi-scale dynamic features and local amplitude disturbances of DC SAF signals, this paper proposes a SAF detection method based on multi-scale generalized amplitude-aware permutation entropy (MS-GAAPE). The method extracts MS-GAAPE from arc current signals at various scales using sliding window-based generalized coarse-graining, which preserves temporal sequence information while improving the characterization of local amplitude variations. Particle swarm optimization (PSO) is applied to optimize these multi-scale features, strengthening fault-related information and reducing interference. The optimized features are then processed by a support vector machine (SVM) for SAF detection. The dataset used contains 50,000 samples covering transient conditions such as voltage fluctuations and is divided into a training set and an independent test set in a 70% to 30% ratio. The training set is utilized for feature parameter determination, feature weight optimization, and classification model construction, while the independent test set is reserved solely for final performance evaluation. Experimental results demonstrate that the proposed method achieves excellent detection performance under various operating conditions and load levels, with an accuracy of 99.32% and a total detection time of 103.62 ms, meeting the requirements of the UL1699B standard, thus showcasing strong real-time detection capability and potential for embedded implementation. Full article

Agricultural Global Value Chains (GVCs) link input suppliers, primary production, processing, and consumption across borders but are increasingly exposed to upstream disruptions. This study develops a network-based Leontief framework to analyze international trade in agricultural GVCs, explicitly modeling fixed-proportions technologies, intermediate input dependence, trade costs, and capacity constraints. It traces how final demand and supply-side shocks propagate through multi-country input–output networks, affecting both quantities and prices. A stylized numerical illustration motivated by war-related disruptions in Ukraine demonstrates how export constraints, trade frictions, and fertilizer shortages can be represented within the proposed framework. The illustrative exercise shows how nonlinear downstream effects may arise mechanically within a fixed-coefficient production network when upstream constraints bind. Fertilizer availability is treated as a potential amplification channel rather than as an empirically estimated determinant of output losses. Full article

Skin functionalities are instrumental in four main domains: protection, regulation, sensation, and support. However, excessive exposure to ultraviolet (UV) radiation can compromise skin integrity and, in turn, affect its functions, by generating reactive oxygen species (ROS). Aiming to protect skin from UV radiation, sunscreens incorporate UV filters and antioxidants that absorb/reflect UV rays and neutralise free radicals, respectively. Nevertheless, undesired side and ecological effects of conventional UV filters have spurred the search for safer alternatives. Among synthetic antioxidants, thioethers have attracted attention for their redox power and potential medicinal properties. In this context, a library of aminopyrimidine–arylthioether conjugates was synthesised and evaluated for their antioxidant, enzyme-inhibitory and antibacterial activities, as well as for their cytotoxicity in HaCaT cells and potential photoprotective properties. Among the aminopyrimidine-thioethers studied, compound C5 stood out for its antioxidant potential, exhibiting a value of 566.39 mM FeSO₄ equivalents per mM of the compound, while compound C2 showed the highest anti-enzymatic potential, inhibiting elastase (45.58%) and tyrosinase activities (34.66%). Regarding photoprotective activity, compound C13 reduced by 33.74% the ROS production induced by UV radiation exposure, at 100 μM, a non-cytotoxic concentration. Finally, compound C7 inhibited the growth of Staphylococcus epidermidis, Staphylococcus hominis and Cutibacterium acnes, at 30 μM. These preliminary results demonstrate that aminopyrimidine–arylthioethers constitute a new class of compounds warranting further investigation for skin protection. Compound C5 showed antioxidant activity in the FRAP assay, comparable to that of the positive control, BHT. Full article

Background/Objectives: Despite available treatment options, glaucoma continues to be a leading cause of irreversible blindness. Current medications have multiple limitations, including rapid drainage, ocular irritation, requirement for multiple daily dosings, and systemic side effects. The current study was designed to engineer and characterize a pregabalin-containing enhanced delivery formulation (PRG-EDF) to directly address these inadequacies. Methods: PRG-EDF eye drops were prepared using ingredients that are either U.S. Food and Drug Administration (FDA)-approved for ophthalmic use or have established safety profiles. The formulation was characterized using multiple evaluations, including pH, zetasizer analyses, viscosity, in vitro drug release, transcorneal permeability, determination of dose concentration and volume, systemic exposure, and potential for tachyphylaxis. Efficacy was evaluated using both Dutch belted rabbits and baboons. Results: PRG-EDF provides extended release for up to 24 h. Ex vivo data reveal that PRG-EDF does not alter the inherent high PRG corneal permeability. An intraocular pressure (IOP) study using DB rabbits demonstrates that 40 µL of PRG-EDF, 0.6%, is the optimum dose of our formulation. Comparison of the efficacy of PRG-EDF with commercial products demonstrated its superiority in overall IOP-lowering efficacy. An extended in vivo assessment demonstrated that the potency of PRG-EDF reached maximum IOP-lowering amplitude after 4 weeks of daily dosing. Moreover, an in vivo bioadhesion assay demonstrated that EDF remained on the ocular surface for up to 24 h. Impressively, PRG-EDF is as effective in baboons as in rabbits. Conclusions: We have successfully engineered a highly promising once-daily glaucoma medication with superior efficacy, as illustrated by higher IOP-lowering ability and prolonged duration of action. Full article

Many species of actinomycete bacteria synthesise glycosylated polyene macrolides that have potential as antifungal drugs. The sugar residues of these compounds have profound effects on potency, toxicity and water-solubility. The medically important antibiotics amphotericin B and nystatin A1 have a single D-mycosamine sugar on C19 of the polyene macrolactone. A few naturally occurring polyenes have a second sugar residue. This may be attached to C35 of 38-membered macrolactones like nystatins or to the equivalent C27 of 30-membered pentaenes like selvamicin. The recently discovered mandimycin has a C35 disaccharide that changes the mode of action, reduces adverse side effects, and delays the emergence of resistance in laboratory cultures of fungal pathogens. Glycosyltransferases that can modify the C27 and C35 positions are of interest to synthetic biologists. The GloSV enzyme is predicted to add a 2,6-dideoxy-D-hexose to C27 of a pentaene in Saccharopolyspora gloriosae. Here we assess GloSV in strains of the amphotericin producer, Streptomyces nodosus. Low levels of new amphotericin analogues modified with D-oliose or D-digitoxose were identified through HR-LCMS. The identification of this glycosyltransferase will assist the development of streptomycete systems for production of non-toxic polyene glycoanalogues. Full article

This paper develops a unified probabilistic framework for the simultaneous assessment of reliability and robustness of series structural systems. Part I formulates an axiomatic theory of structural robustness: the robustness factor F_rob is defined as the negative decadic logarithm of the ratio between the damaged-state system failure probability and a normalised target failure probability, and five formal properties are proven—normalisation, monotonicity in damage severity, exact combination bounds under independent damage scenarios, invariance under reliability-preserving transformations, and boundedness. Part II describes the computational core, the evaluation of series system failure probability: the principal approximation methods (simple bounds, the complement-product reformulation, Ditlevsen’s narrow bounds) are formally derived, and a geometric mean-bound approximation over a dominant-element subset is introduced, with four propositions establishing consistency with bounds, monotonicity, convergence, and a complete characterisation of the error direction under positive equicorrelation, including a provably conservative regime above a threshold correlation. Part III synthesises both parts into a computational framework that evaluates F_rob from first-order reliability method (FORM) outputs alone, avoiding repeated multi-dimensional numerical integration in the inner loop of design optimisation, with an explicit, computable error bound guaranteeing invariance of the robustness classification; a two-sided Slepian envelope further extends this guarantee to systems with non-equicorrelated, non-negative inter-element correlation. The framework is illustrated through a numerical example and validated against a published case study of a glued–laminated timber truss. Full article

Electrochemical nitrate reduction reaction (eNO₃RR) has emerged as a promising alternative to the energy-intensive and carbon-intensive Haber–Bosch process for green ammonia synthesis. However, the intrinsic complexity of the eight-electron transfer pathway and inevitable competing side reactions limit the activity and selectivity of eNO₃RR. Maximizing the utilization of active sites and ensuring structural stability in electrocatalysts are essential for promoting surface proton-coupled electron transfer and improving Faradaic efficiency. Herein, we present a copper metal–organic framework (Cu-MOF)-derived electrocatalyst synthesized via in situ electrosynthesis on copper foam, using cetyltrimethylammonium bromide (CTAB) as a structure-directing agent, followed by electroreduction to produce a self-supported, nano-dendritic structure. This three-dimensional architecture exposes abundant active sites and facilitates electron transport, enabling efficient nitrate-to-ammonia conversion. The optimized CTAB-assisted electrode achieves an ammonia yield of 14.33 ± 0.61 mg h⁻¹ cm⁻² with a Faradaic efficiency of 90.95 ± 2.28% at −1.7 V versus Ag/AgCl. This study introduces a versatile design strategy for copper-based electrocatalysts that integrates structural stability with high activity, offering a sustainable approach for both ammonia production and nitrate remediation. Full article

Pinus pinaster Ait. forests have potential for resin tapping, a forestry activity that complements timber production and may increase the profitability of maritime pine stands. However, the viability of this co-production remains uncertain due to the potential effects of resin tapping on wood characteristics. The present study aimed to investigate the effects of resin tapping on the wood characteristics of maritime pine, in order to infer possible changes in wood quality, its utilisation, and, consequently, its value. The study was based on samples collected in Tresminas from resin-tapped trees (37.2 ± 6.0 years old and mean height of 15.8 ± 1.4 m) subjected to the traditional Portuguese resin tapping method for four consecutive years, and from non-resin-tapped trees (37.5 ± 8.9 years old and mean height of 14.1 ± 2.2 m). Samples were collected from different positions along the stem of resin-tapped trees (incision side, opposite side, and 50 cm above the last tapping incision) and compared with samples obtained from non-resin-tapped trees. Wood density, modulus of elasticity (MOE), modulus of rupture (MOR), extractives content, growth ring width and the number and area of resin ducts were evaluated. The effects of resin tapping on wood properties were assessed by comparing resin-tapped and non-resin-tapped trees, as well as different sampling positions within resin-tapped trees, using linear mixed-effects models. Mean comparisons were performed using Tukey’s test at a 95% significance level. No significant effects of resin tapping were observed on MOE or MOR between resin-tapped and non-resin-tapped trees. Wood from the incision side showed higher density (0.596 g·cm⁻³) and higher extractives content (7.49%). Resin-tapped trees produced a greater number of resin ducts after tapping; however, their area did not change. No significant differences were found in growth ring width between resin-tapped (1.75 mm) and non-resin-tapped trees (1.80 mm), although resin-tapped trees presented slightly narrower rings on average. Resin tapping in P. pinaster did not promote relevant changes in wood properties that would compromise its mechanical and physical performance. Although some alterations were detected, these were predominantly localised and restricted to the region adjacent to the tapping incision. Full article

The limited oxidative stability of fatty acid methyl esters (FAME) constrains their use as biofuels. This study presents a direct, side-by-side comparison of β-carotene and α-tocopherol as natural antioxidant additives in FAME produced from refined rapeseed oil, evaluated under identical thermo-oxidative conditions (100–140 °C). We combine kinetic modelling (first-order and zero-order fits, Arrhenius analysis) with spectroscopic monitoring (UV–Vis for β-carotene; FT-IR for α-tocopherol) and standard oxidation indices (PV, AnV) to link antioxidant depletion to fuel oxidation. Key findings are: (1) β-carotene effectively delays hydroperoxide formation at lower temperatures but degrades rapidly above 120 °C (Ea 6–23 kJ·mol⁻¹), producing secondary products that increase AnV; (2) α-tocopherol shows greater thermal resistance and predictable, dose-dependent protection across the tested range (optimal at 556 µg·mL⁻¹), with higher doses exhibiting potential pro-oxidant effects; (3) activation energies and kinetic orders differ between antioxidants, indicating distinct degradation pathways in the FAME matrix. These results demonstrate that reintroducing natural antioxidants removed during refining can improve biodiesel durability, and that antioxidant selection and dosing must be tailored to expected thermal exposure. The combined kinetic–spectroscopic approach provides a practical framework for optimizing natural additive strategies in biodiesel formulations. Full article

The divalent metal transporter DMT1 (SLC11A2) is implicated in diverse human pathologies including cancers, inflammatory and degenerative diseases. Small molecules targeting this membrane protein are actively searched. Following the identification of the pyranocoumarin praeruptorin A as an inhibitor of ferroptosis that is able to bind to DMT1, we have investigated the interaction of related natural products with DMT1 using molecular modeling to determine structure-binding relationships. Two series of compounds were tested: praeruptorins A-H and qianhucoumarins A-J, all isolated previously from the roots of the Chinese medicinal plant Peucedanum praeruptorum Dunn (Bai-Hua Qian-Hu). The antitumor compound praeruptorin C was identified as the best DMT1 ligand in the series, with a binding capacity largely superior to that of praeruptorin A and also well superior to the reference organoselenium product ebselen, at least from an in silico perspective. Praeruptorin C, and to a lower extent praeruptorins F and H, can form stable complexes with DMT1 upon binding close to the ebselen binding site. Qianhucoumarins C and I were also identified as potential binders. Altogether, the analysis of the 18 natural products enabled identification of structural elements implicated in the target binding process. The curvature of the tricyclic pyranocoumarin scaffold and the angeloyl side chain at position 9 seem to contribute importantly to the protein interaction. An experimental validation is required but the docking study paves the way to the discovery and design of tricyclic coumarin derivatives targeting DMT1. Full article

Large-scale photovoltaic (PV)–hydrogen production systems are increasingly regarded as a promising solution for mitigating renewable energy curtailment and supporting the transition toward low-carbon energy systems. However, when connected to weak grids, such systems often suffer from insufficient voltage–frequency support capability and pronounced Direct current (DC) bus voltage fluctuations, which limit their operational stability and practical deployment. To address these challenges, this paper proposes a dual virtual motor coordinated control strategy for PV-based hydrogen production systems, integrating a grid-forming virtual synchronous generator (VSG) with a virtual DC motor (VDCM). By exploiting the complementary dynamic characteristics of grid-side converters and hydrogen production loads, the proposed approach enhances grid support capability while simultaneously providing inertia and damping to the hydrogen production DC bus without relying on additional physical energy storage. Dynamic response analysis is conducted to investigate the influence of virtual inertia and damping parameters on system stability. Simulation results under weak-grid conditions demonstrate that the proposed strategy effectively improves frequency and voltage support performance and significantly suppresses DC bus voltage fluctuations during load and power disturbances. The proposed control framework offers a practical and scalable solution for improving the operational robustness of PV–hydrogen production systems, contributing to the reliable integration of renewable energy and the development of green hydrogen infrastructure. Full article

A sustainable and scalable one-pot impregnation protocol, avoiding high-temperature calcination/activation, was employed to prepare Pd/Al₂O₃ (0.24 wt%), Pd/TiO₂ (0.18 wt%), Pd/ZrO₂ (0.21 wt%), Pd/SiO₂ (0.37 wt%), Rh/Al₂O₃ (0.18 wt%), and Rh/TiO₂ (0.15 wt%). Support effects on activity, selectivity, and recyclability of these low-metal content heterogeneous catalysts were investigated, using (E)-cinnamaldehyde and levulinic acid as probe molecules. In cinnamaldehyde hydrogenation, Pd catalysts were highly effective for chemoselective C=C reduction to 3-phenylpropanal under mild conditions, with Pd/TiO₂ displaying the highest activity and robust performance over several recycles. However, the Lewis acidity of TiO₂ promoted a solvent-involving side reaction in 2-propanol, with hemiacetal and ether formation, highlighting that apparent selectivity is strongly shaped by support acidity and product residence time. Rh/Al₂O₃ exhibited lower activity than Pd analogues but near-quantitative selectivity to the saturated aldehyde, whereas Rh/TiO₂ again favored hemiacetal formation. In levulinic acid hydrogenation, Pd catalysts were essentially inactive toward ketone hydrogenation even at elevated temperature and H₂ pressure, while Rh catalysts achieved high productivity with exclusive formation of γ-valerolactone, Rh/Al₂O₃ being the most active at comparatively mild pressures. Full article

In order to explore the flow field laws in the electrode plate of a water electrolysis cell and improve its performance, the anode-side bipolar plate of an alkaline water electrolysis cell was taken as the research object. Software was used to analyze the influence of different inlet and outlet forms on the flow field distribution of the electrode plate using the Computational Fluid Dynamics (CFD) method, and the flow field characteristics of different inlet and outlet structures were compared. The simulation results show that there is a large concentration area of fluid velocity near the inlet and outlet channels at both ends of the electrode plate, and the velocity distribution gradually decreases from the inlet and outlet areas towards the center area of the electrode plate. Under the same flow rate, increasing the number of inlet and outlet channels will reduce the fluid flow velocity in the inlet and outlet areas of the electrode plate; increasing the angle of the inlet channel will increase the distribution range of the maximum flow velocity at the inlet and outlet, and reduce the flow velocity difference in other parts. When the inlet flow rate is the same, the flow of fluid on the surface of the electrode plate is more uniform with two inlets than with one inlet; the fluid flow caused by a 20° inlet arrangement is more uniform than that caused by a 15° inlet arrangement. At the same inlet flow rate, the radial inlet configuration yields a more uniform fluid distribution over the electrode plate surface in comparison with the straight-channel inlet design. Full article